Deji Aliu (born 22 November 1975 in Lagos) is a Nigerian sprinter. He won the 100 metres event at the 2003 All-Africa Games. He also took fourth place in the event at the 2002 Commonwealth Games.
Aliu formed part of the Nigerian relay team which won a bronze medal at the 2004 Olympics. Together with Innocent Asonze, Francis Obikwelu and Daniel Effiong he won a bronze medal in 4 x 100 metres relay at the 1999 World Championships in Athletics, but the team was later disqualified (in August 2005) because Innocent Asonze failed a doping test in June 1999.